In this description, these binders will be more especially described in their applications to paints or coatings resistant to marine fouling, without this constituting a limitation in any way, since they will also find many advantageous applications if they are applied alone.
The marine organisms which accumulate on marine underwater surfaces cause an increase of weight and roughness, which constitutes a major problem of ship maintenance both for large-tonnage ships and for fishing and pleasure boats. This phenomenon is more generally known under the name of "fouling."
The fight against marine fouling is now carried out by incorporation of biocidal agents (generally tin salts) in protective paints. The biocidal agents are slowly salted out in the marine medium, so they have a limited effectiveness in time and pollution problems.
EP-A-0 156 632 describes a copolymer comprising acrylic or methacrylic esters which can optionally contain quaternary ammonium functions, but the latter, according to the authors, are not bioactive groups responsible for antifouling activity. Introduction of a hydrolyzable ester is claimed to facilitate erosion of the copolymer. Moreover, the copolymer contains organotin compounds introduced by copolymerization (tributyltin methacrylate, TBTM) which are responsible for the antifouling activity.
FR-A-2 510 121 describes a chemical modification of chlorinated natural rubber intended to make it compatible with polyamides which are claimed to be used for their antifouling activity. Chlorinated natural rubbers are now used in anticorrosion primers, but they do not relate to antifouling finishing coats. Generally, chlorinated polymers are often used in binders for marine paints because of their mechanical behavior and their good resistance to water, but they do not intervene in antifouling properties.
The partial prohibition against using antifouling paints containing tin salts, which are toxic elements for marine organisms of plant or animal origin, has been one of the factors inciting inventors to develop replacement paints not exhibiting these defects.